Astrophytum asterias 'Rensai'
| Light | Bright light; a touch of shade from the fiercest afternoon sun |
|---|---|
| Water | Sparingly; let the mix dry fully between waterings, dry rest in winter |
| Soil | Fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9b–11 |
| Propagation | Seed (selected line); grafting to grow seedlings on quickly |
| Toxicity | Non-toxic to cats and dogs |
Astrophytum asterias 'Rensai, often sold as Rensai Kabuto, is a selected line of the sand dollar cactus in which the white woolly flecks join up into continuous connected chains or streaks that run lengthwise along the ribs, rather than sitting as separate scattered dots. Care is exactly as for the parent species, Astrophytum asterias.
Description
Like all asterias, 'Rensai' is a low, spineless, disc-shaped plant divided into (usually eight) broad, flat ribs, with small woolly areoles spaced in a row down the middle of each rib and a scatter of white flecking over a green to greyish body. What sets the Rensai line apart is the arrangement of that flecking: instead of forming a random speckle, the flecks link and merge into flowing lines and connected chains that trace along the length of each rib, sometimes reading almost as pale stripes. The effect is strongest on well-grown plants and can vary from seedling to seedling, since this is a selected trait rather than a fixed clone. Flowers are the usual asterias type — pale yellow, often with a red-orange throat, opening from the woolly crown in the warm months.
Rensai selections are frequently crossed with, or grown alongside, other patterned asterias lines such as the heavily flocked Super Kabuto, and growers prize individuals in which the connected-line pattern is crisp and well-defined.
Cultivation
Grow 'Rensai' exactly as you would the parent species, Astrophytum asterias. Give it bright light — enough to keep the body compact and the markings well-coloured — with just a little protection from the most intense summer afternoon sun to avoid scorching. Plant in a gritty, fast-draining mineral mix and water sparingly through the growing season, always letting the mix dry out completely before watering again. Keep the plant dry and cool through winter to trigger a proper dormancy, which also helps flowering. Protect from frost.
Because asterias has a shallow, easily rotted root system, err on the side of underwatering, and never leave the plant standing in wet mix.
Propagation
'Rensai' is grown from seed, selecting seedlings that show the strongest connected-line flecking as they mature; because the pattern is a selected line rather than a single clone, expect some variation in each batch. Seedlings are slow, so many growers use grafting onto a vigorous stock to speed them along before growing the best selections back onto their own roots.
See also
- Astrophytum asterias — the parent species
- Astrophytum asterias 'Super Kabuto' — a related patterned line
- Astrophytum — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed